SummaryPorous ceramic bed supports for fused silica packed capillary columns utilized in liquid chromatography were prepared by polymerizing solutions containing potassium silicate in-situ within a column to create a mechanically stable, rugged, and easily constructed termination. The effect of the bed support length on efficiency, and comparisons to glass wool bed supports, were considered in terms of column efficiencies and hydrodynamic variables. Results obtained indicate better performance for the ceramic bed support.

The introduction of selected fractions from a liquid chromatograph into a gas chromatograph has been described; however, analyses were performed by off‐line experiments requiring collection and reinjection of the separate fractions or by on‐line procedures where disadvantageously, only a fraction of the separated peak or a well resolved component in a mixture could be introduced into a gas chromatograph. This disadvantage is overcome by the apparatus and method described in this paper, which utilizes a multidimensional chromatography system employing a high efficiency, packed capillary LC column coupled on‐line to a capillary gas chromatograph. The liquid chromatograph (so designed) can act as a highly efficient clean‐up or chemical class fractionation step prior to introduction into the gas chromatograph, significantly reducing sample preparation times in many applications. Thus minor components in a complex matrix can be determined without prior sample clean‐up, an example of which is the determination of polychlorinated biphenyls in a complex hydrocarbon matrix.

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A rapid liquid chromatographic method for the determination of hexa-, hepta-, and octachlorodibenzo-p-dioxins in pentachlorophenol is described. The nonphenolic impurities are quantitatively isolated from the sample matrix by an extraction-column chromatography procedure that permits the chlorinated dibenzo-p-dioxins to be determined by reversephase partition liquid chromatography. Sample concentrates are analyzed in a 12-min separation with detection limits of 100 parts per billion. The entire analysis may be completed